Clock mechanism with error integrating stopping devices



June 6,-1933. R. H. WHITEHEAD ET AL 1,912,558

CLOCK MECHANISM WITH ERROR INTEGRATING STOPPING DEVICES Filed Oct. 1, 1929 2 Sheets-Sheet 1 INVENTOR. filmd w. m; M

W66 MW 7 ATTORNEYS.

June 6, 1933. R. H. WHITEHEAD ET AL 1,912,558

CLOCK MECHANISM WITH ERROR INTEGRATING STOPPING DEVICES Filed 001;. 1, 1929 2 Sheets-Sheet 2 "Illlllllily .JIIH I INVENTOR.

I v Mm ATTORNEYS.

Patented June 6, 1933 UNITED STATES PATENT OFFICE RICHARD H. WHITEHEAD AND WILSON Ill-PORTER, OF NEW HAVEN, CONNECTICUT, AS-

SIGNORS TO THE NEW HAVEN CLOCK 00., OF NEW HAVEN, CONNECTICUT, A COR- PORATION OF CONNECTICUT CLOCK MECHANISM WITH ERROR INTEGRATING STOPPING DEVICES Application filed October 1, 1929. Serial No. 396,472.

This invention relates to clock mechanism, and more particularly to-clock mechanisms driven by electric motors having means arranged to stop the same upon the attainment of a predetermined integrated error in the time-readings due to motor irregularities.

The invention has for its object generally, the production of a mechanism of the character indicated which is efficient, economical and readily manufactured.

More specifically, it is an object to provide a clock train, propelled by a self-starting synchronous motor, with a means for integrating the error which arises due to current interruptions and temporary stoppages of the time-train, which is adapted to stop the clock when the accumulated error exceeds a predetermined amount.

A further object of the invention is to provide an improved coupling between the motor gearing and the clock-train proper, which is precise and efficient. I

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts, which will be exemplified in the constructions hereinafter set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to thefollowing detailed description taken in connection with the accompanying drawings, in which: w I

Fig. 1 is a front elevation showing a clock mechanism having time indicating hands constructed in accordance with the invention;

Fig. 2 is a side elevation of the clock mechanism shown in Fig. 1;

Fig. 3 is a horizontal sectional view taken on the line 33 of Fig. 2;

Fig. 4 is a vertical section taken on the line 4-4: of Fig. 2;

Fig. 5 is a similar section taken on the line 5-5 of Fig. 2; and

Figs. 6 and 7 are respectively sectional and elevational views showing the details of a special gear employed in connection with the present device.

Referring now to the drawings, 10 and 11 denote respectively front and back plates which, together withthe four supporting columns 12 disposed at the corners of the plates, form a frame for supporting the timetrain and other mechanism employed in the present invention. Between the plates 10 and 11, there is preferably interposed an intermediate plate 13 which supports at its lower end an electric motor of the synchronous type arranged to drive the time-train. The motor has a stator 14 (shown clearly in Fig. arranged for single-phase operation and has an exciting winding 15 thereon and a rotor 16 preferably disposed to rotate between shaded poles so as to be selfstarting, the shading coils for the poles being indicated respectively at 17 and 17. The motor-rotor 18; this gear having a shaft 19 on which is secured a suitable pinion, such as the single toothed pinion 20 here arranged to impart driving impulses to a second-wheel 21 on a center-arbor 22 pivoted in the frame 10-11. This arbor extends horizontally a sufficient distance toward the clock-dial (not shown) to have connected thereto a second-hand 23 which moves about a clock-dial to indicate seconds. The arbor 22 is journalled in the clock-frame so as to have relatively little friction but has mounted thereon a fiy-wheel 24 (shown in Fig. 5) on the periphery of which bears a friction drag-member 25 carried by means of a lever 26 pivoted at 27 in the clock-frame. The force which this friction member applies to the wheel 24 may be altered if desired, and may be made to exceed that due to gravity by means of a spring as shown at 28, having one end secured to the lever 26 with its other end pressed yieldingly against a column 12 of the clock frame. In this way, the frictional drag upon the secondwheel 21 may be made to have any desired magnitude.

On the centre-arbor'22 there is also secured a pinion 30 which meshes with and drives a gear 31 that is supported by an arbor 32 extending through the plate 13 and having at 37 and 38.

The second-wheel 21 which is engaged by the single toothed-pinion 20 at timed intervals, has its arbor 22 at right angles to driving shaft 19 of the pinion 20, and while it may readily be formed to have the ordinary crown gear construction, it is preferred however, that this second-wheel shall be specially formed to increase its efiiciency, for example, by cutting each tooth in a plane oblique to its normal radial plane; the oblique plane being substantially tangent to the arc traversed by the tooth of the pinion 20 when turning to engage with the second-wheel21. The tooth of the pinion 20 is also seen to be slightly off-set from its radial position and advanced slightly to one side, as shown in Fig. 3, since by this advancement, the teeth of the second-wheel 21 are made substantially to engage normally at the initial portion of their engagement with the tooth of the pinion 20 which is when imparting its greatest acceleration. By this arrangement, a highly efiicient transmission of driving force from the motor at 14 to the second-wheel 21 and thence to the clock-train is achieved.

The motor here shown being of the selfstarting synchronous variety and when the word synchronous is used herein it is intended to indicate a motor, the revolutions of which are determined by the frequency, whether actually at full synchronous speed or at some aliquot part thereof. This motor is seen to run whenever the winding at 15 is energized from a suitable source of alternating current, for example, from a 60-cycle, 110- volt source supplied by way of conductors, as shown at 39. If the current for the motor be interrupted from any cause, the driving of the clock mechanism will cease. Driving, however, will be resumed as soon as the current interruption is over. If such interruption of the current takes place without the knowledge of the clock observer, then an unknown error is introduced at the time-read ing. This interruption or a series of the same can introduce a sufiicient error into the reading to make it unsafe. By the present invention, this is avoided, since means are here provided which take account of the motor-stoppages and integrate them so that when the accumulated error is of a predetermined magnitude the clock-train may be stopped until such time as the observer notices the same, resets the hands and starts the clock going again. The predetermined error which is to stop the clock may have any desired value which is deemed to be so great as to make the clock reading unsafe.

The means employed for integrating the error is a device arranged to be controlled by the current and has a timing element which determines the total accumulations of stoppages and consequently of the errors. As here shown, the device comprises a lever 41 pivoted to the plate 13 at 42, so as to have a portion depending adjacent the stator 14, so as to be under the influence of the motors magnetic field, which is induced by the wind ing 15. By this arrangement, the lower portion of the lever 41 operates as an armature adapted to be drawn by the field toward the end of the stator 14 to the full line position shown in Fig. 4. Means for biasing this lever away from engagement with the stator 14 are here employed; such means may conveniently bein the form of a short weighted lever arm as shown at 43 disposed on the pivot 42, connected to the lever 41, and arranged to cause the same to swing away from the unenergized stator to the dotted line position shown in Fig. 4. This lever 41 cooperates with a timing element in the form of an escapement having an inertia wheel 44 which is made to oscillate for a certain period by the energy of a spring 45 (see Fig. 5) which draws down upon a lever arm 46 secured to a shaft 47 pivoted in the clock-frame, this shaft having a driving gear 48 for driving a train which operates the escapement. This driving train is preferably mounted in the clock-frame between plates 10 and 13 above the time-train and may comprise any suitable speed changing gearing, for example, the speed multiplying gearing shown as comprising gear 49 on an arbor having a pinion 50 (see Figs. 6 and 7) that meshes with gear 48. The gear 49 meshes with a pinion 51 on an arbor carrying the escapement wheel 52; the rotation of this latter is controlled by the pallets on anchor 53 which issecured on the arbor of the inertia-wheel 44. The edge of this fly-wheel is preferably milled so as to increase the braking effect when engaged by the lever 41, as shown in full lines in Fig. 4.

The wheel 44 is disengaged when the lever 41 swings to the dotted line position as indicated in Fig. 4. This is seen to occur whenever the field of the motor at 14 becomes de energized, the lever 41 swinging to the dotted line position so as to permit the escapement to operate and dissipate energy of the spring 45. This escapement, as is seen, will run until all of the energy stored in the spring 45 is dissipated whether this running occur during a single interval or during a series of the intervals in which the escapement has run.

Energy is put in the spring 45 by placing the same under tension, for'example by rotating the lever 46 to draw out the. end ating the same to the clock-frame through a short pin as shown at 55 (see Figs. 2 and 5). The spring 45 is thus extended by turning the shaft 47, which may be done in any convenient way, for example, manually through an actuating knob or lever. As here shown, an upstanding lever 56 is employed, disposed on shaft 47 having a bent over portion 56' adapted to exten-dthrough the front dial of the clock so as to be accessible for manual manipulation. Such lever is preferably provided with stops as shown at 59 and 59 to engage with the clock-frame, in order to limit the lever throw and thereby limit the amount of energy that can be stored in the spring 45 by a turn of the lever.

In order that the escapement may not be driven backward when the lever 56 is turned to store energy in the spring 45, yielding motion transmitting connections are provided in the train at some convenient point. This is here accomplished by mounting the driving gear 49 loosely upon its arbor as indicated in Fig: 6, so as to slip on its arbor when turned in one direction, but to transmit driving force when turned in the other.

. This mounting is provided by means of a pawl and ratchet arrangement, the ratchet wheel being shownat 57, fixed'on the arbor of the wheel 49, while the pawl is in the form of a resilient bar 58'secured at one end to the wheel 49. the other being adapted to engage with the notches of the ratchet wheel. The position of the pawl and ratchet is indicated in broken lines in- Fig. 4 where the parts of the escapement driving train are shown in their unenergized position.

It will readily be understood that the amount of energy stored in the spring 45 and the rate at which it drives the escapement, may be proportioned to integrate the periods of current interruption to the motor to any desired total duration and thereby integrate the total error arising from the discontinuity or series of discontinuities in the motor operation. The measure of the integrated error which .may exist up to any instant is the extent to which the energy originally stored in the spring 45 has been dissipated. The position of the lever 56 with reference to the sition of the lever 56 indicates an intermediate amount of accumulated error.

Associated with the escapement train here employed, is a stop mechanism designed to prevent further driving of the clock-train as soon as the accumulated error has reached the predetermined amount determined by the dissipation of all of the energy stored in the spring 45. For this purpose, there is. secured on the shaft 47, a thrust lever or bar 60 which turns with the shaft 47 and is adapted to be engaged by one or more pins disposed at convenient pointsin the clocktrain, for example one on the second-wheel 21 as shown at 61. (See Figs. 2 and 5.) Thus, it is seen when the energy of the spring 45 has been entirely spent the lever 46 and consequently the bar 60 are moved into the positions shown in Fig. 5, whereby bar 60 may be engaged by pin 61 when it comes around to the same to block the wheel and further movement of the clock-train is prevented. It is seen that the stopping of the bar 60 as it turns with the shaft 47 in the right position to be engaged by the pin 61, is insured by the stop 59, this stop being positioned to determine one limit to the throw of the lever 56.

In operation, it is seen that when the clock displacement equal to the distance from one tooth to the next. This distance may be, for

example, the arc space required to indicate one-half second on the dial of the clock,

namely 1/120th of a circumference. Also,

it is seen that the discontinuousengagement- Of theone tooth pinion 20 with the secondwheel 21 causes the latter to advance with a step-by-step movement as it turns to drive the clock-train. Thus, the second hand 23 is seen to move about the face of the clock-dial with a corresponding step-by-step movement, instead of with a continuous movement as heretofore practiced in motor driven clocks, whereby the reading of an elapsed period-in seconds is facilitated.

It is also seen that the friction drag upon the arbor of the second-wheel occasioned by the bearing of the friction member 25 upon the circumference of the wheel 24, prevents the second-wheel 21 from continuing its motion beyond the instant of the driving 1mpulse imparted by the tooth on the pinion 20. Thus, the second wheel is prevented at all times fromover-shooting its desired angular velocity and the clock-train is maintained in discontinuous motion under properly timed impulses as long as the motor at 14 is energized.

When the clock is started, the lever 56 is displaced manually through an are from the position shown in Figs. 1 and 4, where stop 59 engages with one side of the clock-frame to a position where stop 59 engages with the other side of the clock-frame. When in this latter position, the lever 46 has been turned sufficiently upward to extend the spring 45 to the full extent permitted by the movement of the lever 56 and stores a predetermined amount of energy in the spring 45. The dissipation of this energy through the fly-wheel escapement at 44 takes place whenever current is off and this operates as the agent which determines the accumulation of the error in the time reading that occurs when current is off and operates finally to stop the driving of the clock-train.

During the period of current interruption, the armature lever 41 swings away from the motor-stator and consequently away from the escapement wheel 44, so that the escapement train is free to run during this period. The lever 56 as a result moves from its position where stop 59' engages with the clock-frame tothe position where the stop 59 engages with the clock-frame on the other side. If a series of such interruptions be of such total duration that the lever 56 has time to turn through its arc of displacement, then the accumulated error is such as to stop further driving of the time-train. When the lever 56 reaches the position where stop 59 engages with the clock-frame, then bar 60 is in the position shown in Fig. 5 and engages with the stop 61 on the second-wheel 21 to prevent further rotation of the same.

lVhile a stop mechanism has here been described as employed in connection with the device for integrating the accumulated error, it is also seen that the integrating device functions entirely independently of the stop mechanism and may accordingly be used with a clock mechanism without such stop mechanism for the sole purpose of determining the accumulated error. As pointed out above, this latter is determined at any instant from the energy expended by spring 45 or from the position of the lever 56, or the angular displacement of shaft 47 with reference to the clock frame. lrVhen the position of the lever 56 or angular displacement of shaft 47 is relied upon to determine such error, it is obvious that a scale on the clock-dial or at other convenient point may be provided in operative conjunction with these parts to show precisely the position thereof, and thereby indicate visually the amount of the error which has accumulated from the time of setting the integrating device until the time of observation.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not in a limiting sense.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a clock mechanism, the combination with a time-train, of a synchronous electric motor for driving said train, a time integrating device, a brake disposed to stop the operation of said device, and magnetic means disposed under the influence of the field of said motor for actuating said brake when said field is energized.

2. In a clock mechanism, the combination with a time-train, of a self-starting synchronous electric motor for driving said timetrain, an escapement-train associated with said Inotor, means movable to one position for stopping said escapement-train, and to another position permitting the same to start said means being disposed in the field of said motor and arranged to be moved to tramstopping-posit-ion when said field 1s energized, and means actuated by said escapement-train for causing the stopping of said time-tram when the accumulated period, for which said escapement train has run, attains a predetermined value.

3. In a clock mechanism, the combination with a clock-frame having a time-train mounted therein, of a self-startingsynchro nous electric motor associated with said frame and connected to drive said time-train, an escapement train in said frame independent of the time train and means for driving the same, and an armature pivoted in said frame extending into the magnetic field of said motor and adapted to be drawn into engagement with a part of said escapementtrain to stop the same when said field is energized. I

4. In a clock mechanism, the combination with a clock-frame having a time-train mounted therein, of a self-starting synchronous electric motor associated with said frame and connected to drive said train, an independent escapement train in said frame and means for driving the same, an armature pivoted in said frame extending into the magnetic field of said motor and adapted to bear against a part of said escapement-train to stop the same when said field is energized, a stop on said time-train, and blocking means under the influence of said escapement-train arranged to be moved, when said escapementtrain has run for a predetermined total period, into a position where it may be engaged by said stop.

5. In a clock mechanism, the combination with a clock-frame having a time-train mounted therein, of a self-starting synchronous electric motor associated with said frame and arranged to drive said time-train, means under the influence of the magnetic field of said motor for integrating the period of stoppages of said motor, a stop-pin moving with said time-train, and means actuated by said integrating means to move into position for engaging said stop-pin to prevent the driving of said time-train when the integrated error arising from said stoppages has attained a predetermined amount.

6. In a clock mechanism, the combination with a clock-frame having a time-train mounted therein, of a self-starting synchronous electric motor associated with said frame and connected to drive said time-train, independent means adapted to store an amount of energy, means for controlling the rate of expenditure of said energy, means for releasing said energy controlling means whenever said electric motor stops, and means actuated by said energy-storing means for causing the stopping of the driving of said time-train when a predetermined amount of energy has been expended.

7. In a clock mechanism, the combination with a clock-frame having a time-train mounted therein, of a self-starting synchronous electric motor associated with said frame and connected to drive said time-train, means adapted to storean amount of energy, escapement means for controlling the rate of expenditure of said energy independent. of the time train, a brake for said escapement,

and an armature disposed in the magnetic field of said motor and adapted to actuate said brake when said field is energized.

8. In a clock mechanism, the combination with a clock-frame having a time-train mounted therein, of a self-starting synchronous electric motor associated with said frame and connected to drive said time-train, spring means adapted to be moved to a position whereby a predetermined amount of energy is stored, escapement means for controlling the rate of expenditure of said energy, a brake for said escapement, an armature disposed in the magnetic fields of said motor and adapted to actuate said brake when said field is energized, and means actuated by said spring means for causing the stopping of the driving of said time-train when said escapement has released a predetermined amount of energy.

9. In a clock mechanism, the combination with a time train of means actuated by an external source of energy for driving said train and a means responsive to the starting and stopping of said source of energy for integrating the time of stoppage and means for causing the stopping of said tram when a predetermined integrated stoppage has occurred.

10. In a clock mechanism, the combination with a time train of an electric motor for driving said train and means responsive to said electric motor adapted to be brought into operation by the stoppage of said motor and to be rendered inoperative by the starting of said motor, adapted to integrate the duration of motor stoppages and means operable by said integrating said train.

11. In a clock mechanism, the combination with a time train, of a synchronous motor for driving said train, a time integrating device, a brake for stopping the operation of said device and means controlled by the cessation of electrical energy to said motor, for releasing said brake.

12. In a clock mechanism, the combination with a time train of a self-starting synchronous motor for driving the time train, an escapement device and means for integrating the operation of said device, means for controlling the operation of said escapement from the motor to cause the escapement to run during cessation of energy to the motor, and means for stopping the operation of the time train when the escapement device has operated a predetermined time.

13. In a clock mechanism the combination with a time train of a self starting synchronous electric motor for driving said train and means for integrating the period of stoppage of said motor, having an element remalning within the influence of and actuated by the field of said motor, to start the actuation of said means when said motor field fails and means actuated by said integrating means for stopping the driving of said train when the error arising from said stoppages has attained a predetermined amount.

14. In a clock mechanism, the combination with a clock frame having a time train mounted therein of a self-starting synchronous electric motor associated with said frame and connected to drive said time train, means for storing an amount of energy, escapement means for controlling the rate of expenditure of said energy, in ependent of the operation of "said time train, a 'brake controlling said escapement, means for releasing said brake upon failure of the motor current and for applying said brake upon resumption of the current flow.

In testimony whereof we aflix our signatures.

' RICHARD H. WHITEHEAD.

WILSON E. PORTER.

means for stopping CERTIFICATE or CORRECTION.

Patent No. 1,912,558. June 6, 1933.

RICHARD H. WHITEHEAD, ET AL.

It is hereby certified that the signature of the first named inventor at the end of the drawings should have been printed "Richard H. Whitehead" instead of "Richard W. Whitehead"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of August, A. D. 1933.

I M. J. Moore.

(Seal) Acting Commissioner of Patents. 

